Merge branch 'ebassi/c99-macro-varargs' into 'main'

Require C99's __VA_ARGS__

Closes #2681

See merge request GNOME/glib!2791

docs/toolchain-requirements.md

@@ -40,12 +40,12 @@ features’ are assumed.  Those are detailed below.
 
 GLib additionally requires Python 3 to build.
 
-Varargs macros
+C99 Varargs macros
 ---
 
-_Not a hard requirement._
+_Hard requirement._
 
-GLib can work with either C99 or GNU style varargs macros.
+GLib requires C99 ``__VA_ARG__`` support for both C and C++ compilers.
 
 Symbol visibility control
 ---

glib/glibconfig.h.in

@@ -118,8 +118,7 @@ typedef unsigned @glib_intptr_type_define@ guintptr;
 
 @glib_vacopy@
 
-@g_have_iso_c_varargs@
-@g_have_iso_cxx_varargs@
+#define G_HAVE_ISO_VARARGS 1
 
 /* gcc-2.95.x supports both gnu style and ISO varargs, but if -ansi
  * is passed ISO vararg support is turned off, and there is no work

meson.build

@@ -1715,11 +1715,8 @@ g_have_iso_c_varargs = cc.compiles('''
     call_a(2,3);
   }''', name : 'ISO C99 varargs macros in C')
 
-if g_have_iso_c_varargs
-  glibconfig_conf.set('g_have_iso_c_varargs', '''
-#ifndef __cplusplus
-# define G_HAVE_ISO_VARARGS 1
-#endif''')
+if not g_have_iso_c_varargs
+  error('GLib requires a C compiler with support for C99 __VA_ARG__ in macros.')
 endif
 
 g_have_iso_cxx_varargs = cxx.compiles('''
@@ -1729,11 +1726,8 @@ g_have_iso_cxx_varargs = cxx.compiles('''
     call_a(2,3);
   }''', name : 'ISO C99 varargs macros in C++')
 
-if g_have_iso_cxx_varargs
-  glibconfig_conf.set('g_have_iso_cxx_varargs', '''
-#ifdef __cplusplus
-# define G_HAVE_ISO_VARARGS 1
-#endif''')
+if not g_have_iso_cxx_varargs
+  error('GLib requires a C++ compiler with support for C99 __VA_ARG__ in macros.')
 endif
 
 g_have_gnuc_varargs = cc.compiles('''